Process and apparatus for magnetic separation



May 5,1925. 1,535,541

' G. ULLRICH V PROCESS AND APPARATUS FOR MAGNETIC SEPARATION FigPatented May 5, 1925.

UNITED STATES PATENT OFFICE.

GEORG ULLRICH, OF MAGDEBURG, GERMANY. ASSIGNOR TO THE FIRM FRIED.

KRUPP AKTIENG-ESELLSCHAFT, GRUSONWERK, 0F MAGDEBURGr-BUCKAU, GER- MANY.

PROCESS AND APPARATUS FOR MAGNETIC SEPABATION.

Application filed my 1, 1923. Serial No. 636,032.

To all whom it may concern:

Be it known that I, GEoRe ULLRIGH, engineer, citizen of. the GermanEmpire, residing at Winterfeldstrasse 2, Magdeburg, Germany, haveinvented certain new and useful Improvements in Processes and Apparatusfor Magnetic Separation, of which the following is a specification. Thepresent invention relates to a process of magnetic'separation ofmaterials of all kinds according to which the materials are delivered tothe rotating surface of a drum separator. According to this process theseparation is accomplished in such a way that the magnetic material inthe effective magnetic field is retained on the separating surface anddrops outside of the field. The non-magnetic material is previouslythrown off while still in the magnetic field or falls from the rotatingsurface. In this process however, the disadvantage has arisen especiallywhen the material is delivered in a thick layer that a portion of themagnetic material farthest from the ole'edges is not retained, but isdischarged with the nonmagnetic material. This loss of magneticmaterialcan be avoided or at least diminished by delivering the materialtobe separated in a thin layer. Such an expedient however, diminishesgreatly the'output of the separator. It has further been attempted tostrengthen the magnetic influence on the material by fixing inducedrings on the drum, but in spite of the increased magnetic attractionloss of magnetic. material is not avoided.

According to the present invention these disadvantages are avoided bypassing the material to be separated through a plurality of annularzones of a magnetic field arranged concentrically or co-axially around ahorizontal axis, the field. strength of said zones being substantiallyequal or increasin from the inner to the outer.- The materia to beseparated is lead through the outer zone fields to the inmost fieldwhere the main separation takes place. The material not retained inthe-inmost field is thrown outwardly from the rotating drum and durtothe inmost zone field can be so affected, by means of a guide chute forinstance, that it is not influenced during its passage through the outerzone fields and is subjected to a primary separation in the inmostfield. On the other hand, the material tobe separated may be fed freelythrough the outer zone fields to the inmost in such a manner that apreliminary separation is effected in the outer-fields before thematerial reaches the inmost field.

The construction of a separator for car rying out the process accordingto the present invention allows various possibilities of design. Forinstance, the primary pair of poles which form the inmost field.

may be fixed within the drumor allowed 'to rotate with the latter, whilethe secondary pair or pairs of poles which form the outer nal section ofa magnet field, designed for the new process, in three different forms.

Fig. 3 is a top plan View of Fig. 2.

Fig. 5 is a section on the line AB of Fig. 4.

Figs. 6 and 7 show details of'special construction. Fig. 6 being alongitudinal section of a pair, of secondary poles and Fig. 7 a partialview of the separating zone- Fig. 2 illustrates a cross section throughI a'drum according to Fig. 1. on a small scale.

According to the construction illustrated in Figs. 1 to 5 a drum 2rotates about a horizontal axis 1, a pair of poles 3 being fixed withinthe drum. These poles are provided with annular edges 4 which may beattached directly to the poles themselves or to pole pieces provided onthe same. The magnets or poles 3 may be axially displaceable in knownmanner for the purpose of adjusting.

the field. The edges 4 form the primary poles, while the secondary pairof poles 5 is fixed on the outside of the drum 2. The attracting edgesof the rings 5 are sharpened whereby an annular recess 6 is formed be--tween the edges 5 and the drum 2 and this recess can be advantageouslyfilled with a non-magnetic substance. Between the poles 4 and 5 twomagnetic zones 7 and 8 respectively are formed and by means of an axialadjustment of the annular poles the zones 7 and 8 may be made ofsubstantially equal strength or the' outer zone 8 may be made strongerthan the inner zone 7. The introduction of the material to be separatedcan be accomplished for instance, by means of a channel 9 (see Figs. 1and 2) in such a manner that the material must pass through the outerfield 8 on its way to the inner field 7 so as to be primarily influencedby the former. In this manner in its passage through field 8 thematerial is subjected to a preliminary separation. On .the other hand,the material can be conducted to the inmost field in such a manner thatit is not influenced by the outer field (see Figs. 4 and 5.) In thisinstance the guide channel 9 extends into the annular groove formed bythe poles 5. In either instance however, the main separation is affectedin the inner field, that is, on the drum 2 and the greatest portion ofthe magnetic material will be retained by the poles 4. The non-magneticportion as well as that magnetic portion of the material which ,is notretained by the poles 4 will be thrown ofi', but before their escapeboth portions must pass through the outer field 8 whereby a supplementalseparation is efiected.

In the constructional example according to Fig. 8 the primary poles 4also rotate. The field gap between these poles is closed by means of anannular shell 10 which like wise rotates. The method of operation cor--responds to that described above.

The formation of two or more concentric ring zones for carrying out thepresent invention may also be obtained by providing each annular polewith several co-axial edges 11 as shown in Fig. 6. Thus a supplementalmagnetic field is formed between each pair of the edges 11. Moreover,several pairs of secondary poles may be provided in the same manner.

As stated above the strength of the fields can be regulated by providingfor an axial displacement of the annular poles and two or more of suchfield systems can be arranged along the axis of a drum separator.

' The secondary pair of poles can likewise be formed 'by pairs of bandsrunning from one or more guide rollers over the drums. The opposed edgesof the bands form the fields for accomplishing the supplementalseparation. Two or more of such bands can be placed one upon another andthey may be made entirely or partly of magnetic substances.

The annular grooves formed between the pairs of secondary poles are alsowell adapted for wet magnetic separation.

' longitudinal The pole ed es formingthe ring fields may also be provied with teeth running in the direction of their circumference.

As will be seen by the example cited there are numerous possibilities ofseparator conand in what manner the same is to be performed, I declarethat what I claim is:

1. A process of magnetic separation consisting in conducting thematerial to be separated through a plurality of annular zones of amagnetic field, said zones lying in radial succession relative to acentral axis,

whereby. the material passes through the outer field, to the innerfield, andagain through the outer field.

2. A process of magnetic separation consisting in conducting thematerial to be separated through a lurality of annular zones of amagnetic fie d, said zones lying in radial succession relative to acentral axis, the strength of said fields increasin progressively fromtheinmost whereb t e material passes through the outer fie d, to the215131 field, and again through the outer 3. A rocess of magneticseparation consisting in conducting the material to be separated througha lurality of annular zones of a magnetic fie (1, said zones lying inradial succession relative to a central axis whereby the material passesthrough the outer field, to the inner field, and again through the outerfield, the material being first subjected to magnetic influence onreaching the inner field.

,4. A rocess of magnetic separation consisting in conducting thematerial to be separated through a plurality of annular zones of amagnetic field, said zones lying in radial succession relative to acentral axis, the strength of said fields increasing progressively fromthe inmost whereby the material passes through the outer field, to theinner field, and again through the outer field, the material being first'sub'ected to magnetic influence on reaching t e inner field.

5. In a drum separator of the kind as described a pair of primarymagnetic oles y spaced relative to said rum and a'pair of secondarymagnetic poles radially aligned with said primary magnetic poles.

6. In a drum separator of the kind as describ d, a plurality of annularpole pairs arranged in radial succession relative to a described, aplurality of annular pole pairs arranged in radial succession relativeto a central axis, the respective oles of each oi said pole pairs beingspace longitudinally relative to said axis, the material to be treatedbeing passed into the magnetic fields thus formed in a directiontransverse to the axis, the fields of said pole pairs increasing instrength progressively from the inmost to the outer.

8. In a drum separatorof the kind as described, a plurality of annularpole pairs arranged in radial succession relative to a central axis, therespective oles of each of said pole pairs being space longitudinallyrelative to said axis, the material to be J treated being passed intothe magnetic fields thus formed in adirection transverse to the axis,and means for subjecting the material to be separated first to theinfluence of. the

magnetic field of the inmost pole pair.

9. In a drum separator of the kind as described, a plurality of annularpole pairs arranged in radial succession relative to a central axis, thematerial to be treated bein passed into the magnetic fields thus form ina direction transverse to the axis, the opposed edges of said pole pairsbeing provided with circumferential serrations and said serrations beingfilled with a non-magnetic substance.

10. In a drum separator of the kind as dev scribed, an inn'er and anouter pole pair arranged in radial succession relative to the axis ofthe drum, the inner pole pair lying within the drum, the outer pole pairbeing external thereto. V

In testimony whereof the foregoinfg' specification' is signed in thepresence 0 a witness.

GEORG ULLRICH. Witness:

E. H. Gram.

